<html>
<head>
    <meta charset="UTF-8">
    <title>javascript</title>
</head>
<body>
</body>
<script type="text/javascript">
    document.write("使用JavaScript脚本语言循环输出 hello world！")
    for(var i=0;i<3;i++){
        document.write("<h1>你好 世界!</h1>")
    }
</script>
</html>